Built before 1570 by Morrough O’Brien, this once formidable structure had already fallen into ruin by 1839 when antiquarian John O’Donovan recorded it as a ‘ruined castle’. The site appears on both the 1840 and 1916 Ordnance Survey maps, marked as ‘Tullagh Castle (in ruins)’, suggesting its long decline was already well established by the Victorian era.

Today, visitors will find only the barest traces of the castle’s former grandeur; a single corner of an internal wall measuring about two metres in height and length. This fragment represents a dramatic reduction from even the 1930s, when local accounts tell us one wall still stood nearly at its full height. That decade saw the deliberate demolition of the remaining structure, blasted apart to provide building stone for a nearby two-storey farmhouse. Sharp-eyed observers can still spot evidence of this recycling: quoinstones incorporated into the corners of the farmhouse and a fragment of original sillstone lying in the farmyard.

The surviving wall section, measuring 0.68 metres thick, displays classic medieval construction techniques with its double-faced design and mortared rubble core. Archaeologists Ua Cróinín and Breen, who surveyed the site in 1992 and 2014, note that the wall’s width suggests it may have been an internal castle wall, though it could equally represent part of a defensive bawn wall or an outbuilding. Some subtle undulations in the field about ten metres west of the ruins may indicate further buried remains, hinting that Tullagh Castle’s story lies quite literally beneath the surface, waiting to be uncovered.